Two subgroups of schizophrenia identified by systematic cognitive neuropsychiatric mapping.

The description of the heterogeneous phenomenological, pathophysiological, and etiological nature of schizophrenia is under way; however, the relationships between heterogeneity levels are still unclear. We performed a robust cross-sectional study, including a systematic neuropsychological battery, assessment of clinical symptoms, neurological soft signs, morphogenetic anomalies and smell identification, and measurement of event-related potentials on 50 outpatients with schizophrenia in their compensated states. An explorative fuzzy cluster analysis revealed two subgroups in this sample that could be distinguished from each other on symptomatological, cognitive and neurological levels.

Memory awareness following episodic inhibition.

Three experiments used directed forgetting (DF) and retrieval practice (RP) to investigate the relation of inhibited items to states of memory awareness occurring at test. In Experiment 1 using list DF robust inhibitory effects were present in cued recall, but in a recognition test these effects were only present in responses accompanied by recollective experience. In Experiments 2 and 3 using RP reliable effects of inhibition were found but these did not relate systematically to states of memory awareness.

Disrupted memory inhibition in schizophrenia.

A feature of schizophrenia is disrupted executive function leading to learning difficulties and memory problems. In two experiments we measured the ability of patients with schizophrenia to suppress irrelevant parts of acquired information by intentional (executive) and autonomic (non-executive) strategies. In the first experiment using directed forgetting by lists patients were found to be unable to intentionally suppress recently acquired episodic memories.